The invention relates to a device and method for aligning and installing inboard boat engines of varying sizes and configurations.
Inboard engines generally are large, powerful engines, used to drive larger marine vessels. Exclusively inboard engines are typically mounted inside the hull of the boat and mated to a propeller shaft passing through the bottom of the boat hull. Inboard engines can also be part of a marine stem drive. Marine stem drives include both an inboard engine and an outdrive. In a stern drive, the inboard engine is usually coupled to the outdrive, through the transom of the boat, via a drive shaft or the like.
Inboard engines may weigh thousands of pounds. Setting such a heavy engine within the engine bed of a boat commonly requires considerable manpower and the use of heavy machinery. Furthermore, the engine must be precisely vertically and horizontally aligned with both the hull and the propeller shaft of the boat. Since no boat is assuredly manufactured to exact specifications, precisely setting and aligning the engine in a boat is a time-consuming and cumbersome task.
Yet, the need for this precision cannot be ignored. An even slightly misaligned engine can significantly hinder the performance and comfort of a boat. A misaligned engine is often responsible for, among other things, excess vibration, reduced fuel economy and engine efficiency, undue wear on the engine and transmission components and increased strain on the engine mounts and propeller shaft.
An inboard boat engine is conventionally mounted directly upon a pair of longitudinal stringers, extending through the interior hull of the boat, or on stringer brackets coupled to the stringers. Moreover, an inboard engine is necessarily mated to the propeller shaft through the bottom of the boat hull. However, before the engine is secured to the boat and mated to the propeller shaft, it must be precisely aligned. Once the engine is aligned to both the boat hull and the propeller shaft, it is installed. Holes matching the holes on the engine mounts are drilled in either the stringers, or the stringer brackets through which the engine and the boat are joined.
The mount holes are frequently drilled and the propeller shaft aligned while the engine is already set in place. This procedure is problematic. Once the engine has been lowered into place, there is often inadequate clearance within the engine bed to drill the engine mount holes or even align the engine with the boat hull and the propeller shaft.
As a solution to this problem, inboard engine installers began marking the mount holes for subsequent drilling. However, this process requires the engine be removed, the holes drilled and the engine again lowered into place and secured. As explained above, removing and then precisely realigning the bulky engine adds substantial hours of labor to the engine installation. As a result, the manufacturing costs of the boat increase.
Consequently, it is desirable to minimize the adjustments to the engine after the engine has been installed. Accordingly, it is advantageous to precisely locate and drill the engine mount holes prior to dropping the engine into place within the engine bed. It is also desirable that the engine mount holes are precisely located so that the propeller shaft and the propeller drive of the engine are precisely aligned.
In the past, engine alignment and installation tools have been proposed for vertically and horizontally locating engine mounts. U.S. Pat. No. 4,957,462, for example, discusses a tool and method for vertically and horizontally locating front engine mounts of a marine stern drive. However, the ""462 patent does not address the need for locating the rear engine mounts of an inboard boat engine. In addition, the tool of the ""462 patent is not adaptable for use with a broad range of inboard engine makes and models.
Other proposed designs of engine alignment and installation tools have attempted to expand the use of the tool to inboard engines of varying sizes and configurations. These designs may include interchangeable frame members and frame attachments. However, to date, the field of use of the existing engine alignment and installation tool designs is limited to those adapted for use with engines made by a single engine manufacturer.
There is therefore a need for an inboard engine installation jig and method that allows for simple and precise, three-dimensional engine mount and propeller shaft location and alignment, prior to the installation of the engine, and for a wide range of engine sizes and configurations, including engines of multiple manufacturers. There is also a heed for an inboard engine installation jig that is capable of locating and aligning engine mounts on stringer brackets in inboard engine configurations where the engine is not directly mounted onto the stringers.
It is therefore an object of the present invention to provide an engine installation jig allowing for simple, rapid and precise engine mount and propeller shaft location and alignment.
It is another object of the present invention to provide an engine installation jig capable of locating and aligning engine mounts for engine mounting on stringer brackets or directly on stringers of a marine vessel.
It is a further object of the present invention to provide an engine installation jig adaptable for use with inboard engine mounts, stringers, stringer brackets and propeller shafts of a wide variety of original equipment manufacturers.
It is to be understood that other objects and advantages of the present invention will be made apparent by the following description of the drawings according to the present invention.